The present invention relates to the general field of venetian type blinds and is particularly concerned with a venetian blind having segmented tilt adjustment features.
Venetian type blinds are used extensively in numerous settings for dressing various types of windows. They include sets of leaves or slats that can be pivoted between an opened configuration wherein they let in air and light and a closed configuration wherein their peripheral edges override each other to give the desired privacy.
Conventional venetian blinds are controlled by two ropes and four strings.
The ropes are used to lift the whole venetian blind up while the strings control the inclination angle of the slats. The inclination angle of the slats, in turn, allow adjustment of the entry of light.
The two strings are tied to a string attachment which is fixed to a rotary beam in a string hanger protectively enclosed within the top bar.
When an intended user rotates an adjusting rod or wand, the torque is transmitted through a gear box to the rotary beam so that the latter will be rotated about its longitudinal axis.
The rotation of rotary beam, in turn, causes one of the strings to rise and the other one to descend thus modifying the angle of the slats.
In the conventional venetian blind, all the slats are adjusted as an entity. In other words, all the slats are adjusted simultaneously to the same inclination. If one section of the blind is opened, all slats are in the opened position and if one section is closed they are all closed.
In numerous situations, it is desirable to divide the slats into groups whereby each of the groups can be tilted independently of each other and wherein all of the slats can still be raised by manipulation of a rope.
For example, it may be preferred that the slats of the upper half of the venetian blind be kept horizontal to allow light to enter while the slats of the its lower half are adjusted to a steep inclination to intercept light.
This type of blind is especially suitable for use in hospitals, schools, commercial and residential buildings where top lights are desired but wherein it is desired to cut out the view into the room or, for example, in situations it is desirable to intercept incoming sunlight so that articles in the room which are vulnerable to radiation may not be exposed to it.
This problem has been recognized in the past and, hence, there has been numerous suggestions on how to modify the conventional venetian blind so that one section of the blind can be opened while the other is closed.
For example, U.S. Pat. No. 4,621,672 naming Pei-Shun Hsu as inventor issued Nov. 11, 1986 discloses a window blind which includes a regulating mechanism that can set the slats at different inclinations so that when upper slats are opened, lower slats can be closed and vice versa. The regulating mechanism includes a first and a second roller both mounted for rotation about two parallel horizontal axes in the support. A component is provided for driving the first and second rollers separately.
A first regulating string is attached to the first roller and extends downward on the front and rear sides of the shade. The first string has crossed pieces attached thereto at regular intervals for regulating some of the slats.
A second regulating string is attached to the second roller and extends downward on the front and rear sides of the shade.
A second regulating string has second cross pieces attached thereto at regular intervals for regulating the remaining slats. The slats regulated by the first cross pieces are placed above the slats regulated by the second cross pieces.
Although providing independent tilting of two groups of slats, the proposed mechanism suffers from numerous drawbacks including the fact that the regulating strings are arranged in such a manner that they will frictionally abut against adjacent components. The frictional contact, in turn, creates undue stress in the strings which alters their functioning and may eventually lead to breakage thereof.
Numerous other control systems have been proposed but tend to be complicated and bulky, and consequently have failed to provide a satisfactory solution.
Furthermore, they typically require considerable modification to the existing mechanisms and apparently are not too practical inasmuch as none of these devices are commonly available on the market.
Accordingly, there exists a need for an improved venetian blind having segmented tilt adjustment features.
Advantages of the present invention include that the proposed structure allows for a predetermined grouping of slats which can be tilted independently of the remaining slats of the blind. The groups of slats may further be lifted as a whole without altering the tilt control mechanism.
Mainly, the proposed structure is specifically designed so that no tilt adjustment features will hang out of the blind when the groups of slats are lifted as a whole.
Also, the proposed structure is specifically designed so as to minimize friction between adjacent components and particularly to reduce friction between moving strings and adjacent components so as to reduce the risk of altering the functioning of the slat tilt mechanism and reducing the risk of undue wear.
Furthermore, the proposed structure is specifically designed so as to be retro-fittable to conventional venetian blind structures with reduced modifications needed thereto.
Also, the proposed structure is adapted to allow functional use of independent slat tilting without deterring to the overall esthetical aspect of the venetian blind.
Still further, the proposed structure is specifically designed so as to be manufacturable using conventional forms of manufacturing so as to provide a slat tilting mechanism which will be economically feasible, long lasting and relatively trouble-free in operation.
In accordance with an embodiment of the present invention, there is provided a window blind including a shade suspended from a generally elongated head bar, the window blind comprising: at least two generally elongated and horizontal first slats, the first slats being in a superposed relationship relative to each other, each of the first slats having a first slat aperture extending therethrough, the first slat apertures of superposed first slats being in a generally vertically aligned relationship relative to each other; a first tilt string defining a pair of first tilt string segments suspended from the head bar, the first tilt sting segments being in a generally parallel and spaced relationship relative to one another; a set of first supporting strings extending between the first tilt string segments, each of the first supporting strings supporting a corresponding first slat; a first tilt mechanism attached to the head bar and mechanically coupled to the first tilt string segments for selectively allowing relative vertical movement of the first tilt string segments in opposite direction relative to each other so as to pivot the first slats between open and closed configurations; at least two generally elongated and horizontal second slats, the second slats being positioned in an underlying relationship relative to the first slats and in a superposed relationship with each other; a second tilt string defining a pair of second tilt string segments suspended from the head bar, the second tilt string segments being in a generally parallel and spaced relationship relative to one another, the second tilt string segments extending vertically from the head bar through the vertically aligned first slat apertures; a set of second supporting strings extending between the second tilt string segments, each of the second supporting string supporting a corresponding second slat; a second tilt mechanism attached to the head bar and mechanically coupled to the second tilt string segments for selectively allowing relative vertical movement of the second tilt string segments in opposite direction relative to each other so as to pivot the second slats between open and closed configurations; a biasing means for biasing the second tilt string segments towards a predetermined second segment spaced relationship relative to each other in a biasing region located between a lowermost first slat and an uppermost second slat, the biasing means ensuring that the second tilt string segments slide freely within the vertically aligned first slat apertures.
Preferably, each of the first slat aperture defines a corresponding first aperture peripheral edge and wherein the biasing means ensures that the second tilt string segments slide freely within the vertically aligned first slat apertures without contacting the first aperture peripheral edges.
Conveniently, the biasing means includes a retaining clip, the retaining clip defining an inner guiding surface, one of the second tilt string segments being attached to the retaining clip so as to move vertically solidarly therewith while the other second tilt string segments slides freely against the inner guiding surface.
Preferably, the retaining clip has the general configuration of a loop, one of the second tilt string segments being attached to the loop while the other second tilt string segments slides freely against the inner guiding surface defined by the loop.
Conveniently, the loop has a generally oval configuration. Preferably, one of the second tilt string segments is attached to the loop by having an attachment segment of the loop extend therethrough.
Conveniently, one of the second tilt string segments is attached to the loop by having an attachment segment of the loop extend therethrough, the attachment segment of the loop being positioned adjacent a first longitudinal end of the loop; the other second tilt string segments sliding freely against the inner guiding surface defined by a guiding segment of the loop positioned adjacent a second longitudinal end of the loop, the second longitudinal end of the loop being positioned longitudinally opposite the first longitudinal end of the loop.
Preferably, the window blind further comprises a base bar attached to the shade underneath the lowermost second slat; a drawstring defining at least one drawstring segment, the at least one drawstring segment extending from the head bar and being attached to the base bar, the at least one drawstring segment extending through the first slat apertures and through the loops formed by the clips; a drawstring pulling means for allowing the pulling of the drawstring so as to allow the base bar and the first and second slats to be lifted towards the head bar in a shade retracted configuration.
Preferably, the retaining clip is configured, sized and positioned so that when the shade is in the shade retracted configuration, the section of the second tilt string segment extending through the first slat apertures is folded between the first slats without protruding from a peripheral edge of the first slats.
In accordance the present invention, there is also provided in a window blind including a shade suspended from a generally elongated head bar, the shade including a first shade section, the first shade section including at least two generally elongated and horizontal first slats, the first slats being in a superposed relationship relative to each other, each of the first slats having a first slat aperture extending therethrough, the first slat apertures of superposed first slats being in a generally vertically aligned relationship relative to each other; a first tilt string defining a pair of first tilt string segments suspended from the head bar, the first tilt sting segments being in a generally parallel and spaced relationship relative to one another; a set of first supporting strings extending between the first tilt string segments, each of the first supporting strings supporting a corresponding first slat; a first tilt mechanism attached to the head bar and mechanically coupled to the first tilt string segments for selectively allowing relative vertical movement of the first tilt string segments in opposite direction relative to each other so as to pivot the first slats between open and closed configurations; a second individually tiltable shade section comprising: at least two generally elongated and horizontal second slats, the second slats being positioned in an underlying relationship relative to the first slats and in a superposed relationship with each other; a second tilt string defining a pair of second tilt string segments suspended from the head bar, the second tilt string segments being in a generally parallel and spaced relationship relative to one another, the second tilt string segments extending vertically from the head bar through the vertically aligned first slat apertures; a set of second supporting strings extending between the second tilt string segments, each of the second supporting string supporting a corresponding second slat; a second tilt mechanism attached to the head bar and mechanically coupled to the second tilt string segments for selectively allowing relative vertical movement of the second tilt string segments in opposite direction relative to each other so as to pivot the second slats between open and closed configurations; a biasing means for biasing the second tilt string segments towards a predetermined second segment spaced relationship relative to each other in a biasing region located between a lowermost first slat and an uppermost second slat, the biasing means ensuring that the second tilt string segments slide freely within the vertically aligned first slat apertures.